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Dilution calculator

Model a priced round and see what it actually costs you, including the part most founders miss: the option pool top-up.

Short answer

Your new investor's stake is the amount invested divided by the post-money valuation. You keep your share count and own a smaller slice of a bigger total. If new pool shares are created before closing, they sit in the pre-money count, so that cost lands on you rather than the investor.

The round

Who absorbs the pool top-up?

Standard market practice: the pool is sized before closing, so existing holders pay for it.

Your cap table today

Fully diluted today 10,000,000
Post-money
Price per share
Investor takes
New pool shares
HolderSharesBeforeAfterChange
Fully diluted 100% 100%

What this round costs you

Round summary (not an OCF object) What is OCF?

        

The pool shuffle, in one paragraph

Your investor negotiates a percentage of the company after the round. If the pool has to grow to hire the next twelve months of employees, those new shares are usually created before closing, which means they count in the pre-money share total. The price per share drops accordingly, the investor still gets their agreed percentage, and the entire cost of the pool lands on the people who were already there.

This is standard market practice, not a trick. But it is worth knowing that arguing the pool from 15% down to 10% can be worth more to you than arguing the valuation up by a couple of million.

Common questions

How is dilution calculated in a priced round?

Your new investor's stake is the amount invested divided by the post-money valuation. You keep your share count and own a smaller slice of a bigger total.

What is the option pool shuffle?

If new pool shares are created before closing, they sit in the pre-money count, so that cost lands on existing holders rather than the investor.

Does the option pool dilute the new investor?

Only if the top-up is created after the investment so everyone, investor included, absorbs it. Market practice is usually the opposite: existing holders absorb a pre-money top-up.

Run this on your real numbers instead

Connect your cap table to Claude, ChatGPT, Cursor, Gemini or Grok and ask for three pool scenarios in one message.

Connect your assistant Talk it through

This calculator models a single priced round with an optional pool top-up. It does not convert SAFEs or notes, apply participating preferences, or account for anti-dilution. Nothing here is legal, tax or investment advice.